[PATCH v3 60/66] KVM: arm64: Add ARMv8.4 Enhanced Nested Virt cpufeature

[Marc Zyngier]

Add the detection code for the ARMv8.4-NV feature.

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/include/asm/cpucaps.h    |  1 +
 arch/arm64/include/asm/kvm_nested.h |  6 ++++++
 arch/arm64/kernel/cpufeature.c      | 10 ++++++++++
 3 files changed, 17 insertions(+)

diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 6c5b84692a01..31619c73e320 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -17,6 +17,7 @@
 #define ARM64_WORKAROUND_834220			7
 #define ARM64_HAS_NO_HW_PREFETCH		8
 #define ARM64_HAS_NESTED_VIRT			9
+#define ARM64_HAS_ENHANCED_NESTED_VIRT		10
 #define ARM64_HAS_VIRT_HOST_EXTN		11
 #define ARM64_WORKAROUND_CAVIUM_27456		12
 #define ARM64_HAS_32BIT_EL0			13
diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index 36f2cd2c6fdf..c3c57eaa493a 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -14,6 +14,12 @@ static inline bool nested_virt_in_use(const struct kvm_vcpu *vcpu)
 		test_bit(KVM_ARM_VCPU_HAS_EL2, vcpu->arch.features));
 }
 
+static inline bool enhanced_nested_virt_in_use(const struct kvm_vcpu *vcpu)
+{
+	return cpus_have_final_cap(ARM64_HAS_ENHANCED_NESTED_VIRT) &&
+		nested_virt_in_use(vcpu);
+}
+
 /* Translation helpers from non-VHE EL2 to EL1 */
 static inline u64 tcr_el2_ips_to_tcr_el1_ps(u64 tcr_el2)
 {
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index eaeea8a88292..855c37d2f941 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1815,6 +1815,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.field_pos = ID_AA64MMFR2_NV_SHIFT,
 		.min_field_value = 1,
 	},
+	{
+		.desc = "Enhanced Nested Virtualization Support",
+		.capability = ARM64_HAS_ENHANCED_NESTED_VIRT,
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.matches = has_nested_virt_support,
+		.sys_reg = SYS_ID_AA64MMFR2_EL1,
+		.sign = FTR_UNSIGNED,
+		.field_pos = ID_AA64MMFR2_NV_SHIFT,
+		.min_field_value = 2,
+	},
 #endif	/* CONFIG_ARM64_VHE */
 	{
 		.desc = "32-bit EL0 Support",
-- 
2.29.2